Revealing a Native Archeology Site in Starr County

By MOSTH Staff

Imagine standing on a rugged Texas ranch, surrounded by thorny brush and the skulls of longhorn cattle, when suddenly, beneath your feet, a clearing reveals a weathered stone slab—its surface etched with deep, mysterious holes. This isn’t just any rock; it’s a witness to thousands of years of history, a remnant from a time when indigenous peoples roamed these lands, using the slab to prepare their meals and perhaps even survive.

Over 65 million years ago, this very ground lay beneath a vast, prehistoric sea, home to ancient creatures like the mosasaur. As the seas receded, what was left behind was a landscape now characteristic of South Texas—sandy, rocky, and dotted with unique stone formations. Today, these remnants can be found scattered throughout Starr County, on historic ranches, in community spaces, and along the stretch of Interstate 2 leading into Rio Grande City.

But it’s beyond Rio Grande City, in the city of Escobares, that one particular stone slab has captured the attention of rancher and ethnobotanist Benito Treviño. Nestled among thornscrub and the buzz of fire ants, this ancient rock slab features carved-out holes that resemble the traditional Mexican molcajete, used by Indigenous peoples to grind ebony seeds, mesquite beans, and tunas from prickly pear cacti. The holes are in a variety of sizes - some might have functioned like a juicer.

“This grinding stone was used by indigenous people to prepare their food a thousand years ago, perhaps even several thousand years ago,” Treviño explains during a recent visit by Museum of South Texas History staff.

Before showcasing the grinding process, Treviño lights a fire on the sandy ground, demonstrating how native peoples would have roasted mesquite beans—a crucial step in their food preparation. The fire’s heat roasts the pods and burns away cactus needles in a technique known as chamuscar el nopal, setting the stage for the group to use the stone slab as their ancient counterparts once did.

Although Treviño admits there isn’t enough evidence to precisely date the stone slab, he firmly believes it to be an ancient archaeological site.